It is generally recognized in the gas processing industry that chromatographic and/or spectrographic analysis of a two or dual phase NGL fluid product cannot be performed accurately. During conventional fractionation or cryogenic separation processing, the conventional equipment either retains or generates entrained gas in the liquid product. Such is the case, in the first stage of NGL processing where such gas-entrained liquid is typically generated in an output from a cryogenic or de-methanizer tower and, particularly, during the “Ethane Recovery” phase. The resulting analysis of the sample fluid constituents/analytes, accordingly suffer from inaccuracies.
By way of explanation but not intending to be bound to any particular theory, it is believed that the cryogenic process leaves ethane in “dense” phase where the phase change to full liquid state is complete. Because of the substantial magnitude of volume difference of an NGL fluid between its liquid (droplet) form and its vaporized state, accurate and reproducible analysis by, for example, gas chromatography, is rendered almost impossible.
As such, there is a recognized need by processors of NGL for a system to achieve accurate and repeatable measurements usable for process control for NGL product quality assurance and for energy audits, particularly, in the case of custody transfer operations involving storage or transmission vessels.